A toolbox for the chassis: plastic, aluminium or stainless?

Underbody boxes face road salt, vibration and stone impact. Besides the material, the lid direction and the approval of the bracket decide the choice.

2 May 2026Updated 28 September 2026

Short answer

A plastic box is light and cannot rust; the Co.Par Magic Box withstands 50 J of impact. Aluminium chequer plate suits wide, shallow boxes where tools lie side by side, and stainless steel suits the vehicle that sees the most road salt. Before the material, measure the free chassis space and decide which way the lid opens.

An underbody box has to withstand road salt, constant vibration and stone impact, so the material is weighed together with the mounting position, the volume and the lid type.

Material	Example	Strength
Plastic (rotomoulded polyethylene)	Co.Par Magic Box	Light, does not rust, withstands 50 J of impact
Aluminium, 2/3 mm chequer plate	Suer S-Box A	Wide, shallow format, gas-strut lid opening upward
Stainless steel, 1.5 mm matt	Suer stainless range	Rubber seal, lockable, lid opens downward

The Magic Box's ECE R73.01 approval (side guard protection device) is valid only with Co.Par supports; the cataphoresis-painted universal U supports are ordered together with the box.

The lid direction affects the measurements: an upward-opening lid needs clearance above it, a downward-opening one needs clearance in front.

Send Aris Makina the dimensions of the free chassis space and the tool list, and we check the box-and-bracket match against the catalogue.